"Choice" is such a nice word that everybody wants to have it on their side.

"Choice" is also a fuzzy word, which may be why Mitt Romney is willing to call himself a supporter of "school choice". In the strange language of education politics, "choice" sometimes means advocating the partial privatization of school systems through charter schools– which Romney supports. It can also indicate support for voucher programs, which is another thing altogether – and which Romney is said also to support.

Charter schools are constrained by the same laws and policies that, for example, prohibit public schools from endorsing religion. Vouchers, on the other hand, allow parents to use public money to pay for private, mostly religious schools that are largely unaccountable to the public. So, for example, a voucher school may use your taxpayer dollars to teach its students that the earth is 6,000 years old. And a number of such schools now do just that.

You don't have to be a constitutional scholar to get that using public money to fund religious schools violates the letter and spirit of the first amendment. Even the radical conservatives in today's Federalist Society would agree that the US constitution would not allow the government to cut a check to, say, the local mosque in exchange for supplying education to local schoolchildren. That is why they invented "vouchers": by pushing the "choice" to use government money to subsidize religion down to the parents, the government can fund religious schools while pretending that it is not.

The strategy of calling something what it isn't begins at the top. In the Zelman v Simmons-Harris decision of 2002, the conservative majority of the US supreme court lined up in a 5-4 decision to rule that an Ohio vouchers program did not violate the clause of the first amendment that prohibits the government from establishing religion, even though 96% of the students in the program wound up in religiously affiliated schools. The majority claimed that since the parents were free to choose among a variety of schools, the state was not involved in any establishment of religion. In his dissent, Justice Souter observed:

"This result violates every objective the establishment clause has ever been thought to serve."

In 2011, the supreme court once again used linguistic trickery to strike a blow to the separation of church and state. A group of Arizona taxpayers brought suit against their state for a program that used tax credits as means of delivering money from the government to the religious schools of parents' choice. But the five conservatives on the court argued back that since the program relied on a tax credit to individuals, the plaintiffs' taxes themselves were not being used for the program – and so they had no standing to sue. Justice Kagan noted that the garbled reasoning behind the majority decision would make it impossible for any taxpayer to object to government support of religion.

The supreme court decisions helped to set the stage for the present voucher renaissance, but the real action is in the statehouses, where dozens of voucher bills have passed or are up for a vote. In many states, the path to voucherdom follows a carefully plotted route designed to circumvent pesky first amendment concerns. Some of the first voucher programs are aimed at disabled children. After all, who would want to stop disabled children from seeking private education where the state schools are unable to help them?

From the disabled, the programs then expand to cover low-income students and regions. The answer to the problem of grossly underfunded public schools in low-income areas, evidently, is to give them even less money. The long-term vision is to raise the definition of "low-income" to the point where everyone who wants to can funnel public money to their favorite religious academy.

You can learn a lot about a policy idea by seeing who its friends are. Advocates of voucher programs include the activist organizations of the religious right, such as the Alliance Defense Fund and Focus on the Family. School choice activist Mae Duggan, founder of a voucher front group called Citizens for Educational Freedom, who presided over a 2010 meeting in San Francisco with representatives of over 300 pro-voucher organizations, made the motivation explicit:

"We don't want people teaching humanism. Secular humanism is the basis of the public schools."

Another dose of support comes from the libertarian wing of America's shouty political scene. These are the people who think that government is mysteriously cursed with a Midas touch in reverse – everything it touches turns to waste. Clint Bolick, a member of the Council for National Policy and president and founder of the Phoenix-based Alliance for School Choice, quotes his hero Milton Friedman at length describing "government schools" as "a socialist enterprise".

The real money behind the voucher movement, however, comes from real money. Many of the voucher bills passing through state houses are the work of the American Legislative Exchange Council, or Alec, as well as pro free-market thinktanks such as the Heartland Institute and the Heritage Foundation. These organizations engage in aggressive lobbying efforts in favor of what they call "school reform". They are backed by big oil, Koch Industries, Walmart – the kind of corporate entities that Romney would call "people".

Once upon a time, corporations took an interest in supporting strong universal public education because they understood that the long-term health and competitiveness of the economy depends on an informed and rational citizenry. Some good corporate citizens still hold on to that value system. But they are not the ones driving this bus.

What's in it for the money people? In part, it's about the opportunity to make more money. If the public schools are privatized, someone stands to make a lot from government contracts. A more alarming motive, however, is that some of this money hates public education in the same way that the religious conservatives hate it – though with a twist. The religious conservatives hate the teaching of evolutionand other forms of "secularism" they see in every corner of the schoolroom; whereas thecorporations behind Alec and Heartland oppose the teaching of climate science. They both support efforts to "teach the controversy" in their areas of concern. It's hard work to get state legislatures to pass bills undermining the teaching of science – though in Tennessee, they've just done that, following the trail blazed by Louisiana. But if you can use vouchers to funnel the money to private schools that have a more convenient opinion on such matters, problem solved – at least, until the earth boils over.

The problem with pretending that you are doing something that you are not is that reality doesn't have to go along with the game. Voucher programs involve the establishment of religion, and they will inevitably bring with them the harms associated with the undue mingling of church and state. Once government vouchers become a major source of funding for religious institutions, can anyone imagine that the government will not use the power of the purse to curtail teachings of schools run by minority religions that may be considered "cults" or "un-American"? Instead, only perceived majority religions will be allowed to exercise the "right" to teach children according to their own conscience.

In the long run, "school choice" means that students and parents will, in effect, have to choose their religion when they choose their education. The government, in turn, will become captive to the influence of those religious sects that move fastest and acquire the largest share of government funds. And many children will miss out on one of the most valuable lessons that schools can teach: how to get along with those who are different.

Katherine Stewart is the author of "The Good News Club: The Christian Right’s Stealth Assault on America’s Children" (PublicAffairs). Visit her Web site or follow her on Twitter @kathsstewart.